I feel as though there could be two particular Improvements made to the bomber's special ability Kaboooom. Firstly I feel as though it takes too long to get the bomb off and detonate. When the bombers are in the ideal location to be detonated they are likely under heavy fire and sometimes die before getting the bomb off. So the first suggestion would be to reduce the time it takes to detonate Kaboom. Secondly, the range for Kabooom should be increased at least a couple squares. Just my humble opinion.
Alternatively, maybe a damage upgrade. I'm trying to punch a hole in the wall, but with 12 bombers and I still can't break a lvl 11 wall.. That seems a bit overboard to me :/
This has been mentioned before. Kabooom basically only works when bombers are stuck in the walls, or are doing their suicide run between buildings. Any other time, they are too far away from the structures to do real damage. I wish it'd be changed, but until it is, you can make it work week by practicing the timing when the bombers start their run. You want to trigger it when they're between multiple defenses/buildings.
